Rep. Jesse Jackson Jr. announced earlier this week through the Mayo Clinic that he is being treated for bipolar disorder, ending months of speculation about the Congressman’s mysterious medical leave and disappearance from public life in June. But the type of bipolar diagnosis he received — bipolar 2 — has been the subject of widespread controversy among mental health professionals because of its vexing relationship with pharmaceutical marketing and drug patenting.

Classic bipolar disorder, now called bipolar 1 and formerly known as manic-depression, is not a disputed diagnosis. Described across centuries and cultures in recognizable forms, it is a condition characterized by extreme mood swings and affects about 1% of the population. Bipolar 1 manifests in distinct periods of intense elation, or mania, which ultimately involve a loss of contact with reality, alternating with episodes of bitter depression and sadness. In between, patients have normal mood.

Bipolar 2 also involves phases of depression that alternate with elevated mood; however, in this case, patients never experience full-blown mania. Instead, they cycle between depression and “hypomania,” a state that is not so extreme that the person becomes outright delusional. They have feelings of euphoria, speeded-up thoughts and speech, irritability and sometimes increased productivity and creativity, similar to what occurs during a cocaine or amphetamine high.

Bipolar 2 was added to psychiatry’s diagnostic manual, the Diagnostic and Statistical Manual of Mental Disorders (DSM), in 1994. The existence of people who experience the mood swings associated with the disorder is not in doubt, but the prevalence of the condition, its causes and the best ways to treat it are all controversial.

One issue is that diagnoses of bipolar 2 and indeed bipolar disorder in general increased massively, particularly among youth, after the diagnosis was expanded. One study, published in 2007 in the Archives of General Psychiatry, found that between 1994 and 2003, youth visits to doctors resulting in a bipolar diagnosis increased by a factor of 40 and adult diagnostic visits nearly doubled. With the broader diagnosis, the rate of bipolar disorder in the general population rose to 5% — five times higher than previously documented.

Moreover, during the same time period, patents on many of the major new antidepressants were lapsing, starting with Prozac in 2001. That meant far smaller profits for drug companies from these products as generics began to replace the brand names. While antidepressants are not typically used in bipolar disorder since they can aggravate mania, they are used in depression without mania, which does include bipolar 2.

Simultaneously, the pharmaceutical industry began marketing a new generation of atypical antipsychotic medications, along with antiseizure drugs that it labeled as “mood stabilizers.” These drugs were also prescribed for bipolar patients, but while the therapeutic reasons to use mood stabilizers and antipsychotics to treat full-blown mania are sound, the evidence for administering them to treat hypomania is less strong.

Critics of the expansion of the bipolar diagnosis to include bipolar 2, marked by mere hypomania, argue that the move was backed by a big profit motive. Now pharma could recapture the market share it lost when the patents on brand-name antidepressants ran out, simply by relabeling certain cases of depression as depression with hypomania, or bipolar 2. “In recent years, the very same problems have been diagnosed as ‘anxiety’ and then ‘depression’ and now as bipolar disorder — especially bipolar 2,” says David Healy, a psychiatrist, historian of the pharmaceutical industry and author of Pharmageddon.

Not coincidentally, in the 2007 study of youth bipolar diagnoses, most patients were found to have been prescribed a drug combination, with about half including an antipsychotic drug and half including a mood stabilizer.

During this same period, drug companies’ marketing of the new antipsychotics became so aggressive — and illegal — that every major manufacturer of the new generation of drugs would eventually be fined hundreds of millions to billions of dollars for illegal sales tactics, typically involving marketing the drugs for unapproved uses in children.

“The driver, in most cases, lies in the marketing of whichever drug happens to be on patent. In the process, a lot of vulnerable people are providing a transfusion of their lifeblood to ailing pharmaceutical companies who seem insensitive to what happens their victims,” says Healy.

To complicate matters further is the issue of accurately distinguishing bipolar 2 from other types of depression: some cases of apparent bipolar 2 emerge only when people with depression take antidepressants and then experience a first episode of hypomania. Did the medication unmask pre-existing bipolar 2? Or did it cause a short-term episode of hypomania that won’t recur? Or did it trigger a lasting reaction that will be worsened with further antidepressant use? “It’s very hard to know,” says Healy. “[Antidepressants can] certainly trigger hypomania but if in controlling that you end up on [an antipsychotic] and then have enduring problems, what has caused the enduring problems?”

Dr. Allen Frances chaired the task force that initially included the bipolar 2 diagnosis in the fourth edition of the DSM. “Bipolar 2 is an extremely valuable diagnosis that has been overused because of aggressive drug company marketing,” he says. “When accurately diagnosed, it helps reduce the risks of giving antidepressants to people with bipolar tendencies.” When diagnosed incorrectly, however, bipolar 2 exposes people unnecessarily to “the risks of antipsychotic or mood stabilizing meds that can cause dangerous weight gains,” he says.

So how can people like Jackson who have been given the diagnosis find the best treatment? According to Frances, the solution is to require very clear evidence of hypomania before jumping prematurely to the diagnosis — or treatment.

Healy is less optimistic, however, suggesting that people should try, if at all possible, to avoid medications altogether. Of course, that’s not always feasible, which leads to a serious quandary: with the current state of psychiatry so influenced by pharmaceutical marketing, it’s extremely difficult to find safe, effective mental health care, even for a Congressperson.

Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.

As a person diagnosed with Bipolar II, I can't imagine "avoiding drugs". Yes, I would love to give up all of the drugs that keep me stable, but this is not an option. As a recent poster stated, suicide is very high among bp II people. I am one that has been one knife stroke away from suicide, and I don't want to go back to that place!

Maybe, but I have found the combination of drugs very effective. A major problem with bipolar II--a very high instance of suicide. "People should try, if at all possible, to avoid medication" seems to me, to be an irresponsible suggestion.